Somatosensory Evoked Potentials in Term and Preterm Infants in Relation to Postconceptional Age and Birth Weight

Abstract

The effect of age on the maturation of median nerve somatosensory evoked potentials (SEPs) was studied in 103 normal neonates (24 preterm, 79 term) at the postconceptional age (PCA) of 36-48 weeks. The influence of birth weight was evaluated in 44 term neonates, aged 0-7 days, according to their gestational age (GA) stratified into three groups: A: 38-39 weeks (n = 15); B: 39.5-40.5 weeks (n = 15); C: 41-43 weeks (n = 14). The mean birth weight was not different in the three groups. For all infants the N13 latency recorded at cervical (CS2-Fz) level as well as the N19 onset and peak latency at cortical (C3'/C4'-Fz) level were measured. For these parameters and for the N13 latency divided by arm length (N13/AL) and the N19 ascending time (N19AT) the P50, P97 and P3 were calculated as a function of PCA. They were all decreasing in the 36-48 weeks period, fast before 40 weeks and slowly thereafter. The SEP values of groups, A, B and C were not different, but in each group the wave pattern of the cortical SEPs was more mature in the larger than in the smaller infants. For the groups A, B and C together birth weight (in SDS) correlated inversely with the N13/AL and the N19AT (both in SDS) (r = 0.73 and 0.52 respectively, p less than 0.001). Our data indicate that the progression of maturation of the various SEP components in the period of 36-48 PCA is non-linear.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the Relationship between Pain Exposure and Somatosensory Evoked Potentials in Preterm Infants: A Prospective Cohort Study

“…We demonstrated that preterm infants, although without major brain injury, exhibited longer N1 latencies and CCTs, lower amplitudes, and more frequently abnormal SEPs compared to their pair born at term. Our results are supported by those of Smit [ 29 ], who reported that preterm infants presented greater N1 peak latencies compared to full-term babies, both at TEA and at 6 months CA [ 11 , 13 , 30 , 31 ]. These findings could suggest that extrauterine maturation of the somatosensory pathway in very preterm newborns might be delayed compared to the maturation in full-term infants [ 11 , 13 , 30 , 31 ], possibly because of a delay in central myelination but also for the immature functioning of the synapses [ 32 , 33 ].…”

“…Our results are supported by those of Smit [ 29 ], who reported that preterm infants presented greater N1 peak latencies compared to full-term babies, both at TEA and at 6 months CA [ 11 , 13 , 30 , 31 ]. These findings could suggest that extrauterine maturation of the somatosensory pathway in very preterm newborns might be delayed compared to the maturation in full-term infants [ 11 , 13 , 30 , 31 ], possibly because of a delay in central myelination but also for the immature functioning of the synapses [ 32 , 33 ]. Conversely, two other studies did not confirm our results; both studies included infants of older GA with a greater birth weight (GA < 37 weeks and birth weight > 1500 gr), compared to our cohort [ 31 , 34 ].…”

“…In younger preterms, SEPs appear after moderately prolonged delays, and their waveforms typically exhibit small amplitude and long duration, possibly indicating a delayed myelination and immature synaptic connectivity of the nervous pathways [ 14 , 29 , 55 ]. With the progression of the maturation of the central and peripheral pathways, cortical latencies rapidly decrease, with the greatest variation observed between the near-term and term periods [ 12 , 14 , 30 , 34 , 56 ].…”

Use of evoked potentials in preterm neonates.

“…The recording epoch needs to be long, as the components appear at 200-500 ms; a sweep of 1 second is recommended. The waveforms are large, however, and only a few trials (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) are needed per average. Pryds et al 14 report reliable VEPs in premature infants recording only three trials, using very long interstimulus intervals.…”

Somatosensory Evoked Potentials in Neonates with Primary Congenital Hypothyroidism during the First Week of Therapy

“…The selection criteria for this with four groups of term infants: with and without CHT, and group have been described previously (16). In essence, all infants with and without EHB.…”